CHARLOTTE, N.C. (AP) — A senior adviser to President Barack Obama's campaign says the Democrat's convention speech offered plenty of specifics that show voters where he wants to take this country.

Robert Gibbs appeared on "CBS This Morning," a day after Obama's address to the Democratic National Convention.

He says Obama's speech and the broader campaign offer a clear vision as to how the president will improve the lives of middle-class Americans, such as by boosting education and keeping the nation safe.

Gibbs says being a president is a "humbling" thing and Obama understands that "we still have a long way to go" to rebuild the economy.

His comments come as Republican opponent Mitt Romney released 15 television ads in eight states arguing that the nation is not "better off" under the Obama administration.